INS and congestive heart failure: A subanalysis showed that the association between CABG and improved outcome was significant in both insulin- and oral antiglycemic treated patients (Additional file 2: Fig. S1 and Additional file 3: Fig. S2), hypertensive and non-hypertensive patients, those with and without congestive heart failure, and regardless to the number of vessels involved (Additional file 4: Fig. S3).